51 research outputs found
Axima nordestina (Hymenoptera, Eurytomidae), a new stalk-eyed wasp from Brazilian savannah
AbstractA new stalk-eyed wasp Axima nordestina sp. n. is described from the Northeastern Brazilian savannah. Axima nordestina is the fourth species of stalk-eyed wasps (A. noyesi species group) and the second one known from Brazil. The head morphology of A. nordestina appears less derived than in the other known species. An updated key of the A. noyesi species group is provided
Regional diastolic dysfunction in postischaemic myocardium in calf: effect of nisoldipine
Objective: The aim was to assess the effect of nisoldipine on left ventricular systolic and diastolic function during prolonged myocardial ischaemia. Methods: The left circumflex coronary artery was ligated for 2 h and reperfused for 4 h in 12 calves. The animals were randomised to a control group (n=6) or to treatment with 1.25 mg·h−1 intravenous nisoldipine (n=6) during 2 h of ischaemia. Circulatory support by a ventricular assist device was performed throughout the experiment except for the time of haemodynamic measurements. Regional wall thickening of a normal and an ischaemic left ventricular region was determined using pairs of ultrasonic crystals. Left ventricular pressure was measured by micromanometry. Left ventricular wall thickness and regional wall stiffness at a common preload of 10 mm Hg were calculated using an elastic model with shifting asymptote. Results: Ten animals survived after 6 h. No difference was observed in systolic function between controls and nisoldipine treated animals. Systolic thickening of the ischaemic wall remained depressed 4 h after reperfusion and showed some recovery after dopamine infusion. Ischaemic wall stiffness at a common preload was lower after nisoldipine during ischaemia and reperfusion than in controls. Control wall stiffness remained unchanged during the whole experiment with and without nisoldipine. Diastolic thinning of the ischaemic wall was prevented by nisoldipine during ischaemia and after reperfusion. Conclusions: Prolonged myocardial ischaemia is associated with increased myocardial stiffness of the ischaemic wall. Mechanical unloading can help to bridge the acute phase but cannot prevent postischaemic diastolic dysfunction of the ischaemic wall. Nisoldipine has a beneficial effect on regional diastolic function during ischaemia and reperfusion by decreasing regional wall stiffness and preventing diastolic thinning of the ischaemic wall. Cardiovascular Research 1993;27:531-53
Regional diastolic dysfunction in postischaemic myocardium in calf: effect of nisoldipine
Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences
The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported
by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on
18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based
researchers who signed it in the short time span from 20 September to 6 October 2016
Is atrial pacing needed for determination of coronary flow reserve by parametric imaging?
Heart rate changes during determination of coronary flow by parametric imaging may influence the flow measurement. Thus, the question is whether atrial pacing is mandatory for determination of coronary flow reserve (CFR) by this technique. CFR was calculated by digital subtraction angiography (parametric imaging) in 10 patients (8 with coronary artery disease and 2 control subjects) during sinus rhythm and during atrial pacing. Flow measurements were determined in the perfusion region of the left anterior descending and circumflex coronary artery, both at rest and after maximal coronary vasodilation with 10 mg intracoronary papaverine. CFR was defined as coronary flow during hyperemia divided by coronary flow at rest. Spontaneous heart rate was 71 +/- 15 min-1 at baseline, 73 +/- 15 min-1 after papaverine injection and 85 +/- 10 min-1 during atrial pacing. Heart rate variations during coronary arteriography were 4 +/- 3 min-1 at baseline and 5 +/- 4 min-1 after papaverine administration. CFR was 2.61 +/- 1.01 during sinus rhythm and 2.67 +/- 1.05 during atrial pacing. Mean absolute difference in CFR between sinus rhythm and atrial pacing was 0.31 +/- 0.31 (12 +/- 10% of CFR during pacing). Spontaneous heart rate variations during coronary arteriography are not associated with significant changes in CFR. Thus, atrial pacing is not mandatory for the determination of CFR by parametric imaging
Koronararterienkaliber bei chronischer Mitralinsuffizienz vor und nach Mitralklappenoperation. [Coronary artery size in chronic mitral valve insufficiency before and following mitral valve surgery]
The increase of coronary artery size in myocardial hypertrophy represents an adaptive mechanism to keep coronary blood flow normal. The relationship between coronary cross-sectional area and left ventricular muscle mass was determined angiographically in 10 patients with severe mitral regurgitation before and 28 +/- 15 months after successful mitral valve surgery. 10 subjects with atypical chest pain without coronary artery disease served as controls (C). Left ventricular muscle mass was increased preoperatively in mitral regurgitation (257 g vs C = 129 g; p < 0.001) and decreased postoperatively (205 g; p < 0.01 vs preop. and vs C). The cross-sectional area of the left coronary (= left anterior descending+left circumflex) artery was augmented preoperatively (26.5 vs C = 14.0 mm2; p < 0.001) and decreased postoperatively (22.9 mm2; p < 0.05 vs preop. and vs C). The cross-sectional area of the left coronary artery per 100 g LV muscle mass was not different in the three groups. The cross-sectional area of the right coronary artery was also increased before surgery (12.7 vs C = 8.8 mm2; p < 0.05) and decreased postoperatively (11.3 mm2; p < 0.05 vs preop. ns vs C). Our data show that in mitral regurgitation the size of the left coronary artery increases proportionally to the increase in left ventricular muscle mass. Also, the right coronary artery shows slight enlargement which is probably due to the pressure overload of the right ventricle. After surgery there is regression but not normalization of the size of the coronary arteries
Coronary artery size in mitral regurgitation and its regression after mitral valve surgery
The relationship between coronary artery size and left ventricular (LV) muscle mass was studied in 10 control subjects and in 10 patients with chronic mitral regurgitation before and 28 +/- 15 months after mitral valve surgery. Left and right coronary artery size was determined by quantitative coronary arteriography. Left coronary artery size was significantly increased before surgery (26 mm2) and decreased after operation (23 mm2), but was still larger than in control subjects (14 mm2). The right coronary artery was also enlarged preoperatively (13 mm2; controls = 9 mm2), but was normalized after surgery (11 mm2). A linear correlation was found between LV muscle mass and left (r = 0.88, p < 0.001) and right coronary artery size (r = 0.84, p < 0.001) as well as between right coronary artery size and mean pulmonary artery pressure (r = 0.56, p < 0.01). Thus in chronic mitral regurgitation the enlargement of the left and right coronary artery is proportional to the degree of LV hypertrophy. The increase in right coronary artery size is probably the result of right ventricular pressure overload. Postoperatively there is only partial regression of left coronary artery size but normalization of right coronary artery size
Effect of intermittent warm blood cardioplegia on functional recovery after prolonged cardiac arrest
BACKGROUND: There is some evidence that continuous warm blood cardioplegia offers good myocardial protection; however, the effects of interrupting cardioplegia remain controversial. To study this, we compared the effects of continuous and intermittent antegrade warm (37 degrees C) blood cardioplegia on functional recovery after prolonged cardiac arrest (180 minutes). METHODS: Twenty-four juvenile pigs were randomly assigned into four groups. Group 1 received continuous cardioplegia, group 2 underwent several periods of 15 minutes of cardioplegia interrupted by 5 minutes of normothermic ischemia, and group 3 underwent several periods of 10 minutes of cardioplegia interrupted by episodes of 10 minutes. The hearts of group 4 received no cardioplegia. Left ventricular systolic function was assessed from fractional left ventricular shortening and percentage left ventricular wall thickening, and left ventricular diastolic function was determined from the time constant of relaxation and the constant of myocardial stiffness. RESULTS: Systolic and diastolic functions were slightly depressed 1 and 2 hours after cross-clamp removal in all four groups, without significant differences among the groups. CONCLUSIONS: These data suggest that antegrade warm blood cardioplegia can be interrupted for up to 10 minutes without obvious negative effects on left ventricular function in the normal myocardium, provided that the intermittent doses of cardioplegia are sufficient to restore the metabolic demands of the arrested myocardium
Regional diastolic dysfunction in postischaemic myocardium in calf: effect of nisoldipine
OBJECTIVE: The aim was to assess the effect of nisoldipine on left ventricular systolic and diastolic function during prolonged myocardial ischaemia. METHODS: The left circumflex coronary artery was ligated for 2 h and reperfused for 4 h in 12 calves. The animals were randomised to a control group (n = 6) or to treatment with 1.25 mg.h-1 intravenous nisoldipine (n = 6) during 2 h of ischaemia. Circulatory support by a ventricular assist device was performed throughout the experiment except for the time of haemodynamic measurements. Regional wall thickening of a normal and an ischaemic left ventricular region was determined using pairs of ultrasonic crystals. Left ventricular pressure was measured by micromanometry. Left ventricular wall thickness and regional wall stiffness at a common preload of 10 mm Hg were calculated using an elastic model with shifting asymptote. RESULTS: Ten animals survived after 6 h. No difference was observed in systolic function between controls and nisoldipine treated animals. Systolic thickening of the ischaemic wall remained depressed 4 h after reperfusion and showed some recovery after dopamine infusion. Ischaemic wall stiffness at a common preload was lower after nisoldipine during ischaemia and reperfusion than in controls. Control wall stiffness remained unchanged during the whole experiment with and without nisoldipine. Diastolic thinning of the ischaemic wall was prevented by nisoldipine during ischaemia and after reperfusion. CONCLUSIONS: Prolonged myocardial ischaemia is associated with increased myocardial stiffness of the ischaemic wall. Mechanical unloading can help to bridge the acute phase but cannot prevent postischaemic diastolic dysfunction of the ischaemic wall. Nisoldipine has a beneficial effect on regional diastolic function during ischaemia and reperfusion by decreasing regional wall stiffness and preventing diastolic thinning of the ischaemic wall
Axima nordestina (Hymenoptera, Eurytomidae), a new stalk-eyed wasp from Brazilian savannah
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